Recently, HIV (human immunodeficiency virus) protease inhibitors have been developed for the treatment of AIDS (acquired immune deficiency syndrome). With combined use of the protease inhibitors with two HIV reverse transcriptase inhibitors which have been commonly used, treatment of AIDS has made remarkable progress. However, the treatment of AIDS is still not efficient enough for the eradication of AIDS, and development of a new anti-AIDS medicine based on a different mechanism of action is desired.
As a receptor upon invasion of HIV into a target cell, CD4 has already been known. Recently, CCR5 as a second receptor of macrophage directed HIV and CXCR4 as a second receptor of T cell directed HIV, which are G-protein coupled chemokine receptors having a seven-transmembrane protein structure, have been found, and these chemokine receptors are considered to play an essential role for infection and transmission of HIV. As a matter of fact, it has been reported that a human having resistance to HIV infection even after repeated exposures to the virus had a mutation in which CCR5 gene was deleted homozygously. Thus, the CCR5 antagonists have been expected to become a new anti-HIV medicine, and examples of synthesis of new anilide derivatives having CCR5 antagonist activity have been reported in, for example, the below-mentioned patent applications such as Patent Document 1, Patent Document 2, and Patent Document 3, while there has been no report of a CCR5 antagonist which has been commercialized as a therapeutic medicine for AIDS. Further, a compound having CCR5 antagonist activity is described to be useful as a prophylactic and/or therapeutic medicine for AIDS in the below-mentioned Patent Document 4, but the compound has a different structure from the compound of the present invention.
Patent Document 1: WO99/32100
Patent Document 2: Japanese Patent Application No. 10-234388
Patent Document 3: Japanese Patent Application No. 10-363404
Patent Document 4: JP-A No. 2001-026586